developers thought worthy of note. In this article I focus on how modeling the various system components can be used to gain a greater understanding and provide a foundation for evaluating possible changes.

VisuaLiZation by richard aLMond

This type of modeling is not just a
whiteboard or paper exercise. It is the
creation of drivers and components
to emulate various aspects of the sys-
tem. The drivers are used to invoke the
various parts of the system to mimic
its normal behavior. The idea is to ex-
ercise the architecture without the
“burden” of ensuring functional cor-
rectness. At times these drivers may be
scripts written with established tools
(for example, WinRunner, JMeter), but
oping programs specific to the compo-
nent to be driven. These have allowed
me to get the information I needed to
make quality decisions. It is important
to understand that the model compo-
nents and the associated drivers are
not just simple test programs but are
to be used as the basis for exploration
and discovery.

These could span from code changes to infrastructure changes to hardware changes. With the right drivers and component modeling it may become practical to address redesigning some of the components.

Sometimes the functionality contained within a component is so intertwined with the architecture that it’s necessary to create a lightweight replica. It is not unusual for some functional aspects of the system to mask the behavior of the underlying technology or infrastructure in responding to the requesting applications. In these cases having a lightweight model can allow the architectural interactions to be explored and better understood. If you discover architectural solutions,